We have analyzed the magnetic properties of a Fe(III) tetramesityl porphyrinate with 4-cyanopyridine and imidazol mixed axial iron ligands. In contrast to other S4-ruffled porphyrins, which show the novel (da)4dxy configuration with axial g-tensor, g z > g [J. Am. Chem. Soc. 116:7760, 1994], the present compound has a rhombic g-tensor, g = (1.22, 2.07, 3.05), which is comparable to those of b-and c-cytochromes.